#!/usr/bin/env python3

"""
Builds integration branches. Something similar to
  $ git checkout -b branch-name
  $ for b in $(get-branches-from-github) ; do
  >   git pull b
  > done

Requires either `~/.github_token` containing ONLY the token
OR adding an entry like the following to `~/.netrc`:
  ```
  machine github.com
  password ghp_E7ln0tAR34LtoK3nIsw34RyTve2moM3BvK
  ```


Usage:
  build-integration-branch <label> [--no-date]
  build-integration-branch -h | --help

Options:
  -h --help   Show this screen.
  --no-date   Don't add `{postfix}` to the branch name.
"""

import json
import os
import requests
import sys
import time
import netrc

from subprocess import call, check_output
from urllib.parse import urljoin

TIME_FORMAT = '%Y-%m-%d-%H%M'
postfix = "-" + time.strftime(TIME_FORMAT, time.localtime())

current_branch = check_output('git rev-parse --abbrev-ref HEAD',
                              shell=True).strip().decode()
if current_branch in 'mimic nautilus octopus pacific quincy reef squid'.split():
    postfix += '-' + current_branch
    print(f"Adding current branch name '-{current_branch}' as a postfix")

repo = "ceph/ceph"

try:
    from docopt import docopt
    arguments = docopt(__doc__.format(postfix=postfix))
    label = arguments['<label>']
    branch = label
    if not arguments['--no-date']:
        branch += postfix
except ImportError:
    # Fallback without docopt.
    label = sys.argv[1]
    assert len(sys.argv) == 2
    branch = label + postfix

token = ''
try:
    nrc = netrc.netrc()
    nrauth = nrc.authenticators("api.github.com")
    if nrauth:
        token = nrauth[2]
    if not token:
        nrauth = nrc.authenticators("github.com")
        if nrauth:
            token = nrauth[2]
except FileNotFoundError:
    pass
if not token:
    try:
        with open(os.path.expanduser('~/.github_token')) as myfile:
            token = myfile.readline().strip()
    except FileNotFoundError:
        pass
if not token:
    print('No github api access token found')
    print('  Add a token to .netrc for [api.]github.com')
    print('  OR add a token to $HOME/.github_token')

# get prs
baseurl = urljoin('https://api.github.com',
                  ('repos/{repo}/issues?labels={label}'
                   '&sort=created'
                   '&direction=asc'))
url = baseurl.format(label=label,
                     repo=repo)
r = requests.get(url,
                 headers={'Authorization': 'token %s' % token})
if not r.ok:
    print("Failed to access github api")
    print("(Do you have a valid, unexpired github api token?)")
    sys.exit(1)

j = json.loads(r.text or r.content)
print("--- found %d issues tagged with %s" % (len(j), label))

prs = []
prtext = []
for issue in j:
    if 'pull_request' not in issue:
        continue
    r = requests.get(issue['pull_request']['url'],
                     headers={'Authorization': 'token %s' % token})
    pr = json.loads(r.text or r.content)
    prs.append(pr)
    prtext.append(pr['html_url'] + ' - ' + pr['title'])
print("--- queried %s prs" % len(prs))

print("branch %s" % branch)

# assemble
print('--- creating branch %s' % branch)
r = call(['git', 'branch', '-D', branch])
r = call(['git', 'checkout', '-b', branch])
assert not r
for pr in prs:
    pr_number = pr['number']
    pr_url = pr['head']['repo']['clone_url']
    pr_ref = pr['head']['ref']
    print(f'--- pr {pr_number} --- pulling {pr_url} branch {pr_ref}')
    while True:
        r = call(['git', 'pull', '--no-ff', '--no-edit', pr_url, pr_ref])
        if r == 0:
            break
        elif r == 1:
            print(f'Unable to access {pr_url}, retrying..')
        elif r == 128:
            message = f'Unable to resolve conflict when merging PR#{pr_number}'
            raise Exception(message)
        else:
            message = ('Exiting due to an unknown failure when pulling '
                       f'PR#{pr_number}')
            raise Exception(message)

print('--- done. these PRs were included:')
print('\n'.join(prtext).encode('ascii', errors='ignore').decode())
print('--- perhaps you want to: ./run-make-check.sh && git push ci %s' % branch)